Aim for workouts that target your entire core. Planks, side planks, hip ups, mountain climbers, vups are great. Check them out at ab-workouts guide.com under ab workouts, lower ab workouts, and core exercises they're fun and challenging. The key to getting nice tone abs is to do exercises thats force your entire body to work so you can burn enough fat while building lean muscle. Combine that with a nice healthy diet and you're set.